#### Discover the Triangles

*Lesson
Activity: Discover the Triangles*

In this lesson the
student will see that three intersecting lines will create a triangle.
The result is an artistic representation of various kinds of triangles that
has a quality reminiscent of some modernist paintings.

Begin
by drawing random lines across the width and length of the paper, moving horizontally,
vertically and diagonally. The student can us the straight edge for
this. At least a dozen lines should be drawn; more than two dozen lines
will create too many intersections. Now find different triangles
and color them with the color pencils.

Lead the student to find the basic kinds of
triangles: In addition to the triangles shown in the illustrations,
there are also: the *right triangle *(we will study this in the next lesson),
the *acute triangle* (each of the interior angles are less than
90 degrees) and the *obtuse triangle *(one of the interior
angles is more than 90 degrees). At this point we do not need to pull
out the protractor and measure angles; we are simply bringing the various
types to the student's attention. In the main lesson book on the page
adjacent to the artistic rendering, have the student freehand draw the six
types of triangles and label them. The teacher should draw these on
the blackboard or a sheet of paper while explaining the qualities that differentiate
each and the student will then draw the same in the main lesson book.